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Cave pearls are spherical concentric speleothems growing radially around nuclei in shallow pools saturated with calcite. They are very rare in the Southern Levant. We present a unique assemblage of 50 cave pearls found in the Iron Age Joweizeh artificial spring tunnel in the Jerusalem Hills of Israel. Some of these deposits represent the first global evidence of formation on archaeological artefacts: pottery sherds and ancient plaster. Multi‐analyses were conducted to date and characterize the different nuclei and pearls. Charcoal samples extracted from the plaster nuclei of two pearls were 14C dated to the Hellenistic period. Two pearls were formed on sherds of Hellenistic lamps. XPS found Co colour remains, suggesting both had been imported. The Hellenistic date is also supported by archaeomagnetic dates of seven other pottery nuclei. Most Hellenistic remains are probably the outcome of a renovation campaign in the tunnel. Four pearls were sampled for stable isotopes (δ13C and δ18O). The range of δ18O values from the Joweizeh pearls is compatible with the Holocene Soreq and Jerusalem caves’ records. The δ13C differences between Joweizeh and Soreq indicate local changes in the overlying vegetation throughout history. The various lines of evidence enabled us to characterize the pearls’ formation process, reconstruct the Joweizeh spring tunnel's hydraulic environment and detect changes that occurred in its water flow regime throughout history. [ABSTRACT FROM AUTHOR]

This study presents 32 high-resolution geomagnetic intensity data points from Mesopotamia, spanning the 3rd to the 1st millennia BCE. These data contribute to rectifying geographic disparities in the resolution of the global archaeointensity curve that have hampered our understanding of geomagnetic field dynamics and the viability of applying archaeomagnetism as a method of absolute dating of archaeological objects. A lack of precise and well-dated intensity data in the region has also limited our ability to identify short-term fluctuations in the geomagnetic field, such as the Levantine Iron Age geomagnetic Anomaly (LIAA), a period of high field intensity from ca. 1050 to 550 BCE. This phenomenon has hitherto not been well-demonstrated in Mesopotamia, contrary to predictions from regional geomagnetic models. To address these issues, this study presents precise archaeomagnetic results from 32 inscribed baked bricks, tightly dated to the reigns of 12 Mesopotamian kings through interpretation of their inscriptions. Results confirm the presence of the high field values of the LIAA in Mesopotamia during the first millennium BCE and drastically increase the resolution of the archaeointensity curve for the 3rd-1st millennia BCE. This research establishes a baseline for the use of archaeomagnetic analysis as an absolute dating technique for archaeological materials from Mesopotamia.

In this work, we present ArchaeoPyDating, a new version of the archaeo_dating Matlab software used for archaeomagnetic dating. This updated version introduces a transition from the original Matlab code to Python, enabling the software to be presented as an online tool. By offering a web‐based interface, ArchaeoPyDating eliminates the need for licenses, program installations, or programming expertise, making it widely accessible to users through various devices and browsers. This enhanced accessibility holds great potential for popularizing the archaeomagnetic dating method. This study presents both the new online version of the tool and a Python module that encompasses all the essential classes and functions required for conducting archaeomagnetic dating in a command‐line environment, which can be useful for advanced users. [ABSTRACT FROM AUTHOR]

The fortifications of Lachish, a key site in archaeology of the Iron Age Southern Levant, are the focus of ongoing debate. The Outer Revetment Wall, encircling nearly the entire site, was traditionally associated with Levels IV–III and was thought to have been in use during the Assyrian campaign in 701 BCE. It has recently been suggested that it was built a millennium earlier. Here we present archaeomagnetic dating of a mudbrick tower incorporated in this wall, indicating that it was burnt during the Iron Age and was most likely built during this period. Combining archaeological, historical and archaeomagnetic data reveals the intense fire that occurred during the 701 BCE Assyrian siege. This fire could have been set by the people of Lachish, in a desperate attempt to damage the Assyrian siege engines or siege ramp, as depicted in the well-known Lachish relief, or by the Assyrians as part of their siege tactics. [ABSTRACT FROM AUTHOR]

Aotearoa/New Zealand was first settled by the Māori people some 800–1000 years ago. Archaeomagnetism provides one of the few means of dating early sites of Māori occupation, particularly when radiocarbon dating is not feasible. This involves dating the thermoremanent magnetization imparted to the heat-retaining stones used in traditional Māori earth ovens, hāngī or umu, at the time of their last cooling. The direction of this magnetization is correlated with the reference curve of the changes in the geomagnetic field direction in New Zealand over the past 1000 years, NZPSV1k.2023. Here, we describe the application of archaeomagnetic dating to indigenous hāngī sampled at two sites in the North Island of New Zealand. The first, in the present-day city of Napier on the east coast, has been studied in detail and is shown to have been occupied, possibly intermittently, over 400–600 years, while the second, in present-day Waikanae on the west coast, is tentatively dated to ca. 1760 AD, just decades before the first European arrival in New Zealand.

Aotearoa/New Zealand was first settled by the Māori people some 800–1000 years ago. Archaeomagnetism provides one of the few means of dating early sites of Māori occupation, particularly when radiocarbon dating is not feasible. This involves dating the thermoremanent magnetization imparted to the heat-retaining stones used in traditional Māori earth ovens, hāngī or umu, at the time of their last cooling. The direction of this magnetization is correlated with the reference curve of the changes in the geomagnetic field direction in New Zealand over the past 1000 years, NZPSV1k.2023. Here, we describe the application of archaeomagnetic dating to indigenous hāngī sampled at two sites in the North Island of New Zealand. The first, in the present-day city of Napier on the east coast, has been studied in detail and is shown to have been occupied, possibly intermittently, over 400–600 years, while the second, in present-day Waikanae on the west coast, is tentatively dated to ca. 1760 AD, just decades before the first European arrival in New Zealand. [ABSTRACT FROM AUTHOR]

We report the results of an archaeomagnetic study carried out at La Joya, Veracruz, a Classic earthen architecture site located in the central part of the Gulf of Mexico coast. Nineteen datings were obtained, most of which belong to the Early Classic (AD 300-700), when the site had its greatest growth, followed by those from the Late Classic (AD 700-1000) associated to the final constructive phase, including those from the Preclassic corresponding to the beginning of the settlement. The feasibility of applying archaeomagnetism to earthen architecture under tropical climatic conditions was tested, and four Preclassic radiocarbon dates were obtained to be appended to the magnetic secular variation curve of Mesoamerica. [ABSTRACT FROM AUTHOR]

Dating archaeological materials is essential to understand time and rate of changes in different civilizations. For this purpose, different dating methods are used in several materials, including organic remains, sediments, and ceramics. Archaeomagnetic dating is a developing dating tool that has been improving rapidly due to the advances in geomagnetic model curves. The premise of this method is to compare the inclination, declination, and intensity of the geomagnetic field recorded by burnt archaeological materials (i.e., bricks, kilns, burned floors, pit ovens, soils, ceramics, slags), with mathematical models that describe the evolution of the Earth's magnetic field. Different regional geomagnetic models have been built based on local data that allow the application of this dating method, whereas for regions where regional models are lacking, global geomagnetic models are used. In any case, it is essential to assess the intrinsic uncertainties of geomagnetic models to properly evaluate the feasibility of the archaeomagnetic dating. In this context, this work evaluated global geomagnetic models for South America over the last 2000 years, to select the most appropriate statistically for dating purposes. Based on Casas and Tema (2019), a thorough assessment of the age uncertainties of the models was carried out. The statistical analyses of the magnetic parameters of the selected models regarding high-quality data were integrated to the intersection analyses of different magnetic parameters. From this result, this study suggests a geomagnetic multi-model approach as the best configuration for archaeomagnetic dating for South America. • Feasibility of the archaeomagnetic dating tool for South America was tested. • Global magnetic models can be used for archaeomagnetic dating in South America. • Geomagnetic multi-model approach is the best configuration for this case. [ABSTRACT FROM AUTHOR]

The Hebrew Bible and other ancient Near Eastern texts describe Egyptian, Aramean, Assyrian, and Babylonian military campaigns to the Southern Levant during the 10th to sixth centuries BCE. Indeed, many destruction layers dated to this period have been unearthed in archaeological excavations. Several of these layers are securely linked to specific campaigns and are widely accepted as chronological anchors. However, the dating of many other destruction layers is often debated, challenging the ability to accurately reconstruct the different military campaigns and raising questions regarding the historicity of the biblical narrative. Here, we present a synchronization of the historically dated chronological anchors and other destruction layers and artifacts using the direction and/or intensity of the ancient geomagnetic field recorded in mud bricks from 20 burnt destruction layers and in two ceramic assemblages. During the period in question, the geomagnetic field in this region was extremely anomalous with rapid changes and high-intensity values, including spikes of more than twice the intensity of today's field. The data are useful in the effort to pinpoint these short-term variations on the timescale, and they resolve chronological debates regarding the campaigns against the kingdoms of Israel and Judah, the relationship between the two kingdoms, and their administrations. [ABSTRACT FROM AUTHOR]

Beginning in 1964, an academic lineage of Robert DuBois and his students, Daniel Wolfman and Jeffrey Eighmy, developed dedicated United States‐based archaeomagnetic research programs. Collectively, they analyzed over 5,377 archaeomagnetic sites, primarily from North America, dated to less than 2,000 years old. Yet despite their decades of effort, few journal publications resulted. Most of their published results are embedded in archeological reports, often without technical data, which limits the data's accessibility. Furthermore, when published, the results are generally averaged at the site level using statistical conventions different from today's standards, limiting the data's comparability and (re)usability. In 2015, we undertook a salvage archival study to digitize the surviving data and metadata from the scientists' individual estates and emeritus collections. We digitized measurement data from more than 51,000 specimens, reinterpreted them using modern conventions, and uploaded them to the FAIR‐adhering magnetic data repository, earthref.org/MagIC. The reinterpreted site‐level results from the three laboratories are mutually consistent, permitting the individual data sets to be combined and analyzed as single regional entities. Through incorporation into the MagIC repository, these legacy data are now accessible for incorporation into archaeomagnetic and global magnetic field modeling efforts, critical to understanding Earth's magnetic field variation through time. In the Four Corners region of the United States Southwest, this digitized archive advances the development of a new regional paleosecular variation curve used in archaeomagnetic dating. This project highlights both the value and complexities of managing legacy data; the many lessons learned to set a precedent for future paleomagnetic data recovery efforts. Plain Language Summary: Archaeomagnetism is the study of Earth's past magnetic field through researching the magnetic signatures retained in well‐dated archeological materials. The most commonly studied materials are those that have experienced high temperatures due to human‐made fires. Due to humans' global occupation, there is a potential for globally distributed archaeomagnetic sampling, which is essential for high‐resolution global magnetic field models. However, there is considerable variation in the documentation and accessibility of data from certain regions, including North America. In 2015, a salvage archival project was initiated to recover the life's work of three North American archaeomagnetists. The effort resulted in the digitization and formatting of the data within DuBois' and Wolfman's estates, and Eighmy's archive. In total, measurement data from more than 51,000 specimens, from 5,377 archeological features, were processed and uploaded to a centralized online data repository, MagIC. This repository ensures that the data, representing 130 person‐years of work, are now findable and accessible, permitting the data to be re‐used in future modeling projects. One such application for these data is the development of a new regional model for the Four Corners region of the United States Southwest that traces the location of the magnetic north pole through time. Key Points: We digitized 6 decades of legacy archaeodirectional measurements from three archives (>51k specimens), adding them to a FAIR repository, MagICThe site‐level results (reanalyzed using modern statistical conventions) are consistent between the archivesThe majority of the data have site provenance in North America and are dated to less than 2,000 years old [ABSTRACT FROM AUTHOR]

The Altos de Jalisco region is still poorly understood in terms of its cultural dynamics. Extensive relationships have been identified with other nearby cultural areas, especially with the Bajío and the Lerma-Santiago River Basin. Much of the settlements so far discovered in this region belong to the Epiclassic period (600-900 AD) whose settlement pattern is similar with sites established on nearby plateaus. Many of these sites are build-up of sunken courtyards, closed squares, as well as palaces with columns that suggest hierarchical societies. One of these sites that stands out in this region is the Presa de la Luz extensively investigated since 2012. Our interest is to recognize the role and dynamics in context of Los Altos de Jalisco zone and its relationship with other surrounding areas. Within the site, there is a complex of buildings called El Cerrito de Los Agaves, where series of deep (about 4 m) burned floors were identified. Archaeomagnetic dating of apparently two independent floors provides age intervals around 1000 AD. Presumably, these dates correspond to the period of abandonment of the site since they are remarkably similar to the ages reported for the Plazuelas (Guanajuato) site (105 km east of this site). These results were also compared with the architecture of the place and the archaeological materials from excavation, mainly ceramics. It may be concluded that this part of the Altos de Jalisco belongs the same regional social dynamics during the Epiclassic. [ABSTRACT FROM AUTHOR]

Teotihuacan is one of the most studied archaeological sites in Mesoamerica because of its exceptional size and urban planning; however, its last years of occupation and abandonment are still under debate. We report a high-resolution chronology for the Xalla complex integrating archaeomagnetic dates, radiocarbon (14C) ages, and detailed archaeological information about sample type and context in a Bayesian model. The model includes 42 14C ages and 7 archaeomagnetic dates grouped in 6 phases, including samples from collapsed roofs with 14C ages earlier than expected, suggesting a problem of inbuilt age. The archaeomagnetic dates on lime plasters were classified in unburned samples, related to the time of construction, and burned samples, related to the Big Fire associated to the abandonment of Teotihuacan. The modeled 14C ages resulted in shorter intervals, with the possibility of differentiating the construction phases, confirming that big beams had inbuilt age. Further, combining the two dating methods and classifying lime plaster samples in burned and unburned, it was possible to date different events within the same archaeological context. It is concluded that by combining these two dating methods and understanding the moment that each sample is dating, it is possible to obtain solid and precise chronologies. [ABSTRACT FROM AUTHOR]

We present the first Italian reference secular variation curves for both direction and intensity that cover the last 3000 years. Strict selection criteria were applied to guarantee the collection of the most reliable data within a 1000 km radius of Viterbo, including archaeomagnetic records from archaeological material and volcanic rocks. The new curves are calculated using Bayesian statistics and they depict interesting geomagnetic field features, such as high‐intensity periods. These are the first curves for Italy, including both directional and intensity data, and they can be used as reference curves for archaeomagnetic dating, not only in Italy but also in nearby countries. [ABSTRACT FROM AUTHOR]

Lime kilns excavated in the Mayan area may be considered suitable artifacts for archaeomagnetic studies because the production process generally requires temperatures higher than 700 °C. This fact guarantees that the walls and floors of the furnaces carry the stable thermoremanent magnetization acquired during the cooling from high temperatures during its last use. 12 of a total of 17 samples, collected and oriented in situ inside the furnace located in Sitpach, Merida were thermally demagnetized in order to obtain their characteristic archeodirections (declination and inclination). The site-mean direction was determined based on 7 samples with greater clustering. Archaeomagnetic dating yielded two possible intervals: 267-671 AD and 1279-1455 AD. Based on relative chronological considerations of the area, the second interval seems more feasible. This new absolute chronological contribution, together with those previously reported, indicates the continuity and permanence of pyrotechnological knowledge in the Maya area from 900 to at least 1600 AD, including the beginning of the colonial period, in which some furnaces, probably built before the Spanish conquest, were reactivated. [ABSTRACT FROM AUTHOR]

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Five fired clay structures from the Northeast sector of the Early Neolithic settlement of Yabalkovo in the Maritsa valley, Bulgaria were a subject of an archaeomagnetic investigation. The results of the detailed rock-magnetic experiments carried out show that the collected materials are suitable for archaeomagnetic study and reliable determinations for past geomagnetic field elements can be obtained. According to the mean values calculated for the ancient geomagnetic field direction and intensity, two different periods of time can be undoubtedly distinguished for the investigated structures. This coincides exactly with the two chronological horizons suggested by the excavators. The archaeological observations point that the oven in sq. K36, the hearth in sq. F16 and the hearth in sq. H31 are related to Horizon II, while the hearths in sq. I31 and sq. F18 are connected with Horizon I. Based on the Bulgarian reference curves (latest version), the following archaeomagnetic dating intervals are received: Yabalkovo – Horizon II – (5685–5489 BC) and Yabalkovo – Horizon I – (5472–5427 BC). These results agree well with the archaeological data that structures from Horizon II are older than structures from Horizon I. The existing 14C dates (for materials taken mainly from the Southwest sector of the settlement) show considerably older dating intervals but they are not able to differentiate chronologically the different structures. The obtained archaeomagnetic determinations for Yabalkovo are compared with these available for other archaeomagnetically studied Early Neolithic sites from Bulgaria and Northern Greece. This comparison indicates that Horizon II of Yabalkovo can be synchronised with the younger layers of Kovatchevo (Karanovo I), Stara Zagora (Karanovo II) and Dobriniste. Horizon I of Yabalkovo is chronologically comparable with Horizons VII+VIII of Samovodene and Avgi (Nortern Greece).

We report comprehensive rock-magnetic and archaeointensity investigations from 21 well-constrained pottery fragments from the Catamarca province of northwest Argentina. The absolute ages of the studied sites are ascertained by several high-quality radiometric ages and range between 1940 to 114014C yr BP. Magnetic mineralogy experiments indicates that the remanence is carried by thermally stable Ti-poor titanomagnetites. Forty-seven samples belonging to 11 out of 98 studied potsherds yielded reliable absolute intensity determinations judging from the quality parameters associated with the Thellier double-heating experiments. Moreover, we analyzed the available absolute geomagnetic intensities associated with the radiometric ages to construct the first intensity paleosecular variation curve (PSVC) for South America using thermoremanent magnetization carried by burned archaeological artifacts obtained in the present investigation and 79 other selected archaeointensities (out of 213 published in the literature). The dataset is used to build the PSVC reference curve by combined bootstrap and temporal P-spline methods. The variation curve shows significant differences with the global prediction model SHA.DIF.14k mainly based on the GEOMAGIA database. This intensity PSVC curve shows reasonably good agreement with paleosecular variation curves for Europe between 850 through 1150 BC and for Asia between 1000 and 1500 BC. This regional curve may be used as most reliable archaeomagnetic dating tool for the major part of South America (Peru, Brazil, Argentina, Chile, and Bolivia) for the last two millennia. [ABSTRACT FROM AUTHOR]

Despite the immense cultural heritage of Mesoamerica, there is still no reference archaeomagnetic curve available for Central Mexico and adjacent areas. The present research has two simultaneous objectives: to obtain finer characteristics of the geomagnetic field elements over archaeological past, and to build up a reliable regional archaeomagnetic dating tool for the time span of 350 BC. to 1500 AD. For these purposes, 72 previous were compiled and analyzed with 40 new data selected from unpublished reports and theses performed in the paleomagnetic laboratories of the Geophysics Institute of UNAM (CDMX and Morelia). Most of the samples carry thermo-remanent magnetization, 31 cases were unburned stuccos, and 3 mural paintings carrying detrital or pictorial remanent magnetization. A total of 112 archaeomagnetic directions constitute the core of the updated catalogue. Special effort should be paid for to the time intervals of 500 BC.--AD. 200 and AD. 1200-325 where there is a major lack of reliable archaeomagnetic results. The present paleosecular variation curve agrees reasonably well with the fluctuation observed in the SW United States area. The differences in the intervals between AD. 600-720, AD. 850 and 1000 and AD. 1200-1325 may be rather attributed to the lack of reliable data than to local non-dipole field. It is urgent to gather a greater number of high-quality data supported by radiometric ages to improve the reference curve in both regions. [ABSTRACT FROM AUTHOR]

Abstract The aperiodic nature of geomagnetic field variations, both in intensity and direction, can aid in dating archaeological artefacts, volcanic rocks, and sediment records that carry a palaeomagnetic signal. The success of palaeomagnetic dating relies upon our knowledge of past field variations at specific locations. Regional archaeo- and palaeomagnetic reference curves and predictions from global geomagnetic field models provide our best description of field variations through the Holocene. State-of-the-art palaeomagnetic laboratory practices and accurate independent age controls are prerequisites for deriving reliable reference curves and models from archaeological, volcanic, and sedimentary palaeomagnetic data. In this review paper we give an overview of these prerequisites and the available reference curves and models, discuss techniques for palaeomagnetic dating, and outline its limitations. In particular, palaeomagnetic dating on its own cannot give unique results, but rather serves to refine or confirm ages obtained by other methods. Owing to the non-uniform character of magnetic field variations in different regions, care is required when choosing a palaeomagnetic dating curve, so that the distance between the dating curve and the record to be dated is not too large. Accurate reporting and incorporation of new, independently dated archaeo- and palaeomagnetic results into databases will help to improve reference curves and global models for all regions on Earth. [ABSTRACT FROM AUTHOR]

In Mexico, the Teoloyucan Geomagnetic Observatory has been operating regularly since 1914, providing an almost continuous record of the secular variation of the Earth's magnetic field. This work offers a synthesis of the geomagnetic record obtained in Mexico for more than one hundred years. With these data, we propose a regional secular variation curve which, given its technical quality, is proposed as an archaeomagnetic dating tool for this time interval. [ABSTRACT FROM AUTHOR]

We present a new curve of the directional secular variation of the geomagnetic field in Western Europe between 1500 bce and 200 ce. Its computation relies on a Bayesian framework. The fast secular variation during the Late Bronze and Early Iron Ages makes archaeomagnetic dating efficient with a respective precision of 150–200 and 60–100 years during these periods. The Bayesian method also provides posterior date distributions that refine the dating of reference data, especially during the period of the Hallstattian radiocarbon plateau. Archaeomagnetism becomes a valuable alternative to radiocarbon and will help to improve the archaeological chronologies. [ABSTRACT FROM AUTHOR]

In this contribution, we present a combined archaeomagnetic and luminescence study of archaeologically dated structures. The investigated area is a ceramic workshop comprising several Early Byzantine kilns. Based on (a) the archaeological-anthropogenic stratigraphy of the site, (b) the structural characteristics of the kilns and (c) the few ceramic findings revealed within their context, the operation of this brick and tile factory is approximately dated between the middle of the fifth century until the first decades of the sixth century AD. Three of the well-preserved workshop kilns have been studied archaeomagnetically. The full vector of the geomagnetic field, accompanied by rock magnetic analyses of the studied material, has been defined. The archaeomagnetic study revealed similar directions among the three kilns indicating and confirming their contemporary use. Additionally, several luminescence measurements were obtained on material from the same kilns. The dating of the site was performed with both methods. The archaeomagnetic dating is convergent with the archaeological estimation only when its upper limit is considered. Concerning the luminescence dating, the calculated ages (corrected for anomalous fading and for the 40K content) with their standard deviations are convergent with the archaeological estimations for the first kiln, while for the other two, the results seem to be incompatible. The possible factors that provoked this divergence are thoroughly discussed. [ABSTRACT FROM AUTHOR]

Archaeomagnetic dating was performed on four archaeological structures in Catalonia (NE Spain) using magnetic inclination and declination values from three reference curves: the Iberian SVC and two curves computed using the regional SCHA.DIF.3k model and the global SHA.DIF.14k. The results provide new data for discussions regarding the dating of three archaeological sites from three very different periods: Roman, Medieval and Modern. In addition, some considerations were made regarding the usefulness of the three reference curves and the corresponding geomagnetic models. The Iberian SVC suggests that a Roman limekiln near Tarragona was last fired during the 1st century BC, but the archaeomagnetic models suggest it was last fired during the 1st century AD, i.e. closer to the date of the kiln infillings (2nd–3rd centuries AD). All three-reference curves date two structures from an archaeological site to the north of Barcelona to the 10th or 11th century AD. These ages match those determined using radiocarbon ages. Dating a modern limekiln near Girona with a presumed age of more than 200 years produced an inconsistent age when using the Iberian SVC, but plausible ages in the 17th or 18th centuries AD using the archaeomagnetic models. This suggests that the Iberian SVC has been superseded by the regional SCHA.DIF.3k model and the global SHA.DIF.14k model, both of which exhibit excellent dating capabilities. Older archaeological sites, including prehistoric sites, should be investigated to fully exploit and verify the potential of the new SHA.DIF.14k archaeomagnetic model. [ABSTRACT FROM AUTHOR]

Copyright of Proceedings of the Prehistoric Society is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Two dome ovens from the archaeological complex of Pliska Palace, North-Eastern Bulgaria, were sampled and studied using archaeomagnetic method. These two ovens are well dated archaeologically, and their archaeomagnetic results will elucidate better the sought geomagnetic field variations for the given time period. On the other hand, we have the possibility to demonstrate the applicability of the archaeomagnetic method for dating purposes. Detailed rock-magnetic analyses were performed in order to establish the magnetic properties of the collected materials (stability of carried remanence, type of dominant magnetic minerals, domain state of magnetic particles and degrees of mineralogical transformations during heating). In general, the investigated materials are suitable for archaeomagnetic determination. The applied experiments show that they have not been heated to temperatures over 460oC as the temperature of heating in oven No2 was probably slightly higher in comparison to that in oven No1. Taking into account the determined mean values for the geomagnetic field elements, it is obvious that both ovens have been used in the past within two different time periods. The mean declination of oven No1 is more than 20 degrees lower than the declination of oven No2. Differences between the two other geomagnetic field parameters, inclination and intensity, are less pronounced: 5 degrees for inclination and 3 μT for intensity. An archaeomagnetic dating was done on the basis of Bulgarian reference curves from 2013. There is a very good agreement between the determined archaeomagnetic dating intervals (894–993) AD (for oven No1) and (1001–1075) AD (for oven No2), and the archaeological assumptions. These results confirm the importance of the archaeomagnetic method in archaeology as a reliable dating tool.

Many decades of archaeological research in the Mimbres region have resulted in hundreds of chronometric dates obtained from contexts dating prior to A.D. 1450, but until now these data have not been compiled into a single database. Using dendrochronological, radiocarbon, and archaeomagnetic dates, we analyze each of the chronometric data sets to identify patterns and biases that help us better understand the tempo and duration of fundamental transitions in the Mimbres archaeological record. We also identify critical gaps in our knowledge of the chronometric record that provide new research opportunities. [ABSTRACT FROM AUTHOR]

Archaeomagnetic dating offers a valuable chronological tool for archaeological investigations, particularly for dating fired material. The method depends on the establishment of a dated record of secular variation of the Earth's magnetic field and this paper presents new and updated archaeomagnetic directional data from the UK and geomagnetic secular variation curves arising from them. The data are taken from publications from the 1950's to the present day; 422 dated entries derived from existing archaeo and geomagnetic databases are re-evaluated and 487 new directions added, resulting in 909 entries with corresponding dates, the largest collection of dated archaeomagnetic directions from a single country. An approach to improving the largest source of uncertainty, the independent dating, is proposed and applied to the British Iron Age, resulting in 145 directions from currently available databases being updated with revised ages and/or uncertainties, and a large scale reassessment of age assignments prior to inclusion into the Magnetic Moments of the Past and GEOMAGIA50 databases. From the significantly improved dataset a new archaeomagnetic dating curve for the UK is derived through the development of a temporally continuous geomagnetic field model, and is compared with previous UK archaeomagnetic dating curves and global field models. The new model, ARCH-UK.1 allows model predictions for any location in the UK with associated uncertainties. It is shown to improve precision and accuracy in archaeomagnetic dating, and to provide new insight into past geomagnetic field changes. [ABSTRACT FROM AUTHOR]

Deliberated dental modifications and mutilations are known since prehistoric times. The Mayas and other ancient cultures in Mesoamerica were considered pioneers of such practice. The evidences of therapeutic intervention, however, are still poorly documented and credible examples are extremely scarce. One of the burials excavated at the locality of La Mina (Michoacan, Mexico) corresponds to a 30-35 year old male individual named Alvaro, who presented a well-marked dental deformation. Moreover, Alvaro had a quite deep and symmetrical perforation in the upper right canine-a treatment similar to the procedure of endodontics or root canal. The archaeological context of Alvaro's habitat was dated using the archaeomagnetic method applied to pottery samples unambiguously correlated to the burial. The analysis supplied a time interval between 647 and 825 AD suggesting the first evidence of complex dental practice in the Americas. [ABSTRACT FROM AUTHOR]

This study contributes to the pre-Hispanic chronology of Western Mexico through archaeomagnetic dating of the archaeological site Guachimontones (Teuchitlán, Jalisco). Systematic magnetic measurements were carried out to determine the mean direction of each sample at the UNAM paleomagnetism laboratories (Mexico City and Campus Morelia). Sixteen analyzed samples (81 specimens in total) come from furnaces, burned and unburnt floors, collected between 2005 and 2010. Archaeomagnetic dates with precision parameter α95 < 10° were obtained for 88% of the samples, and corresponds to the site occupation periods. This study thus contributes new and reliable data to the reference variation curve of Mesoamerica in addition to documenting architectural modifications in the building sequence at Guachimontones and supporting the theory of reoccupation of this site during the Epiclassic period (450-900 A.D.). [ABSTRACT FROM AUTHOR]

Researchers have related the manufacturing technique of plasters and stucco in the Maya area with their period of production but not with their architectural function. In this paper, we establish a relationship between those three features (manufacturing technique, age, and architectural function) in the plasters of the Maya site of Dzibanché in southern Quintana Roo. Dzibanché has abundant remains of stuccos and plasters found mainly in three buildings (Plaza Pom, Pequeña Acrópolis, and Structure 2). We used thin sections, SEM and XRD, and archaeomagnetic dating processes. The pictorial layer of Structure 2 was the earliest (AD 274-316 and the stuccoes and plasters of the other two buildings were dated to the Middle Classic (AD 422-531), but we obtained different archaeomagnetic dates for the red pigment layers found in the buildings of the Pequeña Acrópolis and thus we were able to determine their chronological order of construction. The raw materials and proportions were carefully chosen to fulfil the mechanical necessities of the architectonic function: different proportions were found in plasters of floors, in the external walls, and inside the buildings; differences between earlier and later plasters were also detected. [ABSTRACT FROM AUTHOR]